Diodes & transistors worksheet with answers

Free printable Diodes & transistors worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
+−Vs​10 VR1​ = 330 ΩR2​ = 1.5 kΩID​ = ?

A 10 V DC source is connected through resistor R₁ = 330 Ω to a node X. From node X to the source’s negative terminal there are two parallel paths: resistor R₂ = 1.5 kΩ, and a silicon diode with its anode at X. Use the constant-drop model with 0.7 V. Find the diode current ID in mA.

Vs = 10 VR1 = 330 ΩR2 = 1.5 kΩVD = 0.7 V
ID = mA
2.Easy
+−Vs​10 VR1​ = 470 ΩR2​ = 1 kΩID​ = ?

A 10 V DC source is connected through resistor R₁ = 470 Ω to a node X. From node X to the source’s negative terminal there are two parallel paths: resistor R₂ = 1 kΩ, and a silicon diode with its anode at X. Use the constant-drop model with 0.7 V. Find the diode current ID in mA.

Vs = 10 VR1 = 470 ΩR2 = 1 kΩVD = 0.7 V
ID = mA
3.Medium
RC​ = 1.5 kΩβ = 100RE​ = 1 kΩVCC​ = 15 VR1​ = 56 kΩR2​ = 15 kΩ

An NPN transistor with β = 100 has voltage-divider bias from VCC = 15 V: R₁ = 56 kΩ from VCC to the base and R₂ = 15 kΩ from the base to ground. The collector resistor is RC = 1.5 kΩ and the emitter resistor is RE = 1 kΩ. Take VBE = 0.7 V and use the Thévenin equivalent of the divider (do not neglect the base current). Find the collector–emitter voltage VCE.

VCC = 15 VR1 = 56 kΩR2 = 15 kΩRC = 1.5 kΩRE = 1 kΩβ = 100
VCE = V
4.Medium
RC​ = 2.7 kΩβ = 150RE​ = 1.2 kΩVCC​ = 20 VR1​ = 68 kΩR2​ = 10 kΩ

An NPN transistor with β = 150 has voltage-divider bias from VCC = 20 V: R₁ = 68 kΩ from VCC to the base and R₂ = 10 kΩ from the base to ground. The collector resistor is RC = 2.7 kΩ and the emitter resistor is RE = 1.2 kΩ. Take VBE = 0.7 V and use the Thévenin equivalent of the divider (do not neglect the base current). Find the collector–emitter voltage VCE.

VCC = 20 VR1 = 68 kΩR2 = 10 kΩRC = 2.7 kΩRE = 1.2 kΩβ = 150
VCE = V
5.Hard
RC​ = 1 kΩβ = 100VCC​ = 9 V3.3 VRB​ = ?

An NPN transistor with β = 100 switches a 1 kΩ load resistor connected between VCC = 9 V and its collector. The emitter is grounded. The base is driven from a 3.3 V logic output through a base resistor RB. Take VBE = 0.7 V and VCE(sat) = 0.2 V. Find the largest base resistor RB, in kΩ, that still drives the transistor just into saturation.

VCC = 9 VRC = 1 kΩβ = 100Vin = 3.3 VVBE = 0.7 VVCE(sat) = 0.2 V
RB = kΩ
6.Hard
RC​ = 220 Ωβ = 80VCC​ = 5 V5 VRB​ = ?

An NPN transistor with β = 80 switches a 220 Ω load resistor connected between VCC = 5 V and its collector. The emitter is grounded. The base is driven from a 5 V logic output through a base resistor RB. Take VBE = 0.7 V and VCE(sat) = 0.2 V. Find the largest base resistor RB, in kΩ, that still drives the transistor just into saturation.

VCC = 5 VRC = 220 Ωβ = 80Vin = 5 VVBE = 0.7 VVCE(sat) = 0.2 V
RB = kΩ

Answer key

  1. 1. ID = 27.72 mA
  2. 2. ID = 19.09 mA
  3. 3. VCE = 9.508 V
  4. 4. VCE = 14.25 V
  5. 5. RB = 29.55 kΩ
  6. 6. RB = 15.77 kΩ

Full step-by-step solutions: practise this topic on examproblems.com.